Silverfish is a valuable small-scale economic fish that is suitable for growing in larger waters. In recent years, large and medium-sized reservoirs have been cultivated in the north. It lays eggs in winter and the suitable water temperature is 0°C to 8°C. The artificial hatching technique is as follows: I. Preparation Prepare two 50 ml and 200 ml measuring cups, two 200 ml and 500 ml graduated cylinders, 5 burettes, 5 suction cups, 5 each for tweezers and scissors, 2 thermometers, 4 trays, 1 balance, Malachite 50 grams of green, 20 kg of salt. Several 140 cm 20 cm fertilized bags are made of 6-filament polyethylene film. A number of 1.2 m 2 m 0.2 m hatching pools were built, made of bricks, then covered with polyethylene film and disinfected with 15% salt water. Second, catch broodstock Silverfish usually mature in the middle and late December in the north, and artificial insemination begins when mature individuals reach 30%. The broodstock were caught and gill nets of 1.8 cm to 22 cm were used. The fishing area is generally at a depth of about 2 meters, where the sediment is gravel. Third, artificial insemination (1) Identification of male and female broodstock. Females, through their transparent abdomen, can see mature eggs arranged in the abdominal cavity. The abdomen expands, presses the abdomen slightly, and the granules flow outward. The male fins are thick, with only one testis smaller and a white vas deferens near the cloaca. Mature males are red at the heart. (2) Artificial insemination. Dry the broodstock with a dry towel and place it in the tray. Take the insemination bag and fold it into a tube. Hold the insemination bag with the middle finger, ring finger and little finger of the left hand. Then take the female and pick up the head. The right thumb and the other four fingers are folded together. The thumb presses the abdomen of the female and squeezes the egg. Into the fertilization bag. Then, with the right hand, pour the male fish. The head of the fish is pointing to the arm. The anal fin is 1 cm away from the fish's egg. The semen is squeezed out and the male fish is placed on the fish eggs. Add 30 ml of 0.7% physiological saline to the fertilized bag and grasp the bag mouth to shake it up and down to make it fully mixed. Fill the insemination bag with air, then use a rubber band to tie it well and let it rest for 30 minutes. Then remove the male fish in the fertilized bag, add 100 ml of filtered river water, and let it sit in the hatching tank. IV. Incubation and Management of Fertilized Eggs (1) Add the filtered water to the water depth of the hatching pond to a depth of 5 cm to 7 cm, remove immature egg masses and impurities from the fertilized bag, and then place the fertilized egg in the hatchery tank with a density of 500,000 grains/m2. (2) Remove unsterilized dead eggs with a straw every morning. (3) Change the filtered water by 1/2 to 1/3 every day, and the water temperature difference should not exceed 1°C. (4) Two days later, eggs of malachite green were used at a concentration of 0.110-6 for half an hour. The unfertilized egg floats on the upper layer, and the fertilized egg sinks quickly and is transparent and bright, in the lower layer. Incubation is generally completed within 6 days to 8 days.
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